Releasable safety ski binding having a self-restoring capability

ABSTRACT

A releasable, safety-type ski binding which holds a ski boot in normal skiing relationship on a ski and permits the boot to separate from a ski under the influence of abnormal forces in order to prevent injury, while remaining leashed thereto, and self-restores the boot and ski to skiing relationship once such forces abate. The binding includes a soleplate detachably connected to the ski boot and operatively coupled to the ski by heel and toe connecting units carried by the soleplate and an associated pair of mounting elements secured to the ski. Each connecting unit has an elongated, flexible leash secured at one end to its associated mounting element and arranged for extension and retraction to serve as the force-applying link between the boot and ski, and a spring acting to apply tension to the leash to yieldably resist extension, and, to retract it and draw the boot and ski into, and hold them in, such skiing relationship. The tension force is high when the leash is retracted and progressively reduces during initial extension thereof, yet remains sufficiently high at all times to retract the leash in the absence of abnormal forces applied to the boot or ski.

United States Patent [1 1 Weinstein et a1.

[ RELEASABLE SAFETY SKI BINDING HAVING A SELF-RESTORING CAPABILITY [75]Inventors: Burton A. Weinstein, New York;

Gordon C. Lipe, Skaneateles, both of NY.

[73] Assignee: National Recreation Industries, Inc.,

Stamford, Conn.

[22] Filed: Apr. 4, 1973 [21] App]. No.: 347,870

[52] US. Cl 280/1135 N [51] Int. Cl. A63c 9/08 [58]Field0fSearch...280/l1.35 N, 11.35 K, 11.35 R

[56] References Cited UNITED STATES PATENTS 3,448,989 6/1969 Marker280/1135 N 3,489,424 [/1970 Gertsch et al... 280/1135 K 3,549,16312/1970 Wiedermann 280/1 1.35 N 3,764,154 10/1973 Witting 230111.35 K3,822,070 7/1974 Salomon 280/1135 N 3,825,274 7/1974 Weinstein 280/11.35 N FOREIGN PATENTS OR APPLICATIONS 279,445 3/1970 N 72,653 11/1959 C523,079 7/1940 United Kingdom .4 280/] 135 B 1,951,923 4/1971 Germany280/1135 K 179,790 l/l936 Switzerland 5 N 227,994 10/1943 Switzerland280/1135 N [451 July 8,1975

Primary Examiner-Leo Friaglia Assistant ExaminerMilton L. SmithAttorney, Agent, or Firm-Fulwider, Patton, Rieber, Lee & Utecht 1 57]ABSTRACT A releasable, safety-type ski binding which holds a ski boot innormal skiing relationship on a ski and permits the boot to separatefrom a ski under the influence of abnormal forces in order to preventinjury, while remaining leashed thereto, and self-restores the boot andski to skiing relationship once such forces abate. The binding includesa soleplate detachably connected to the ski boot and operatively coupledto the ski by heel and toe connecting units carried by the soleplate andan associated pair of mounting elements secured to the ski. Eachconnecting unit has an elongated, flexible leash secured at one end toits associated mounting element and arranged for extension andretraction to serve as the force-applying link between the boot and ski,and a spring acting to apply tension to the leash to yieldably resistextension, and, to retract it and draw the boot and ski into, and holdthem in, such skiing relationship. The tension force is high when theleash is retracted and progressively reduces during initial extensionthereof, yet remains sufficiently high at all times to retract the leashin the absence of abnormal forces applied to the boot or ski.

25 Claims, 18 Drawing Figures PATENTEUJUL 8 ms RELEASABLE SAFETY SKIBINDING HAVING A SELFRESTORING CAPABILITY CROSS-REFERENCE TO RELATEDAPPLICATION This application is related to copending application Ser.No. 255.375 now U.S. Pat. No. 3,825,274, en titled "Ski Binding WithAutomatic Boot-To-Ski Return. on an invention of Burton A. Weinstein, aco-inventor herein.

BACKGROUND OF THE INVENTION This invention relates to a releasable.safetytype ski binding and, more particularly. to an improved bindingwhich permits the boot and ski to yieldably separate when the forcesapplied to either exceed a safe level and which also incorporates anautomatic boot-to-ski return capability.

It is now common practice to couple a ski boot to a ski with a safetybinding that releases the boot from the ski in the event of an abnormalforce situation, as would otherwise pose a risk of injury. A widevariety of types of such bindings have been provided, and most haveadjustment features to enable the break-out or release force level to bevaried in accordance with the skill. physical characteristics andcondition of a given skier. Many also incorporate a "step-in" capabilityto permit the skier to couple conveniently the boot to the ski byaligning the boot with the ski and binding and stepping down on the ski.To prevent complete escape of the ski once a release has occured,various types of separate leash arrangements have been provided.

The binding disclosed in the above-identified copending application ofBurton A. Weinstein represents a departure from conventional practice.It not only releases the boot and ski from normal skiing relationship inevent of abnormal forces, but automatically returns them to suchrelationship when the forces have abated. This is accomplished by twobinding or leash units mounted on the ski adjacent the heel and toe ofthe boot, and each having an elongated, flexible leash which isconnected to an adjacent portion of the boot or soleplate and whichcomprises the force-applying link between the boot and ski. Each unitfurther includes a drum that receives the leash and rotates under theinfluence of a tension mechanism to yieldably permit leash extension andto retract the leash. The tension force on the leash is at a highpreselected level during a skiing phase when the boot and ski are innormal skiing relationship. However, the application of an abnormalforce sufficient to overcome the preselected tension force causesinitial separation of the boot and ski, and the tension then drops offina release phase to permit the boot and ski to separate more readilythrough a substantial distance, so as to prevent injury. After theperiod of abnormal force has passed, the boot and ski are automaticallydrawn back together and, when they are in close proximity, the bindingreturns to its skiing phase to again exert a high tension force on theleash.

The tensioning mechanism of the prior Weinstein binding comprises twosprings. One of these springs acts during the skiing phase to exert thehigh level of tension. but is disabled during the release phase. Theother exerts a reduced tension force on the leash during at least therelease phase.

Although the design of the earlier Weinstein binding disclosed in thenoted copending application is highly satisfactory, further improvementin certain areas is deemed desirable. In particular, it is advantageousto have a binding readily adjustable to accommodate dif ferent bootsizes without adversely affecting preselected release settings orwithout necessitating remounting on the ski. In this same regard, it isdesirable to simplify procedures for properly mounting a binding on aski. Providing these features with a binding embodying heel and toeunits mounted on a ski has proven to be difficult. From a performancestandpoint, it is important to have the binding readily and accuratelyadjustable to permit separation of the boot and ski at preselected forcevalues and to have those values remain unchanged to any material extentunder skiing conditions. Still another highly desirable attribute is tohave the desirable release and return characteristics noted. yet to doso without unduly increasing overall binding weight or cost. Simplicityof construction which. in turn, enhances trouble-free operation is stillanother desirable attribute.

SUMMARY OF THE INVENTION A ski binding in accordance with the presentinvention has both release and return capabilities and, additionally,mounting, adjustment, weight, cost and per formance advantages overprior bindings.

A soleplate or other boot-receiving support detachably coupled to theboot carries the operative parts of the binding, including a connectingunit comprising an elongated, flexible leash which extends and retractsduring functioning of the binding and constitutes the force-applyinglink between the boot and ski. Biasing means yieldably resists suchextension and causes the leash to retract. A mounting element disposedon top of the ski and secured to it receives the leash and completes theforce link between the boot and ski.

The biasing means acts to exert a high level tension force on the leashwhen the leash is retracted and the soleplate and mounting element arein close proximity to one another. The force decreases during leashextension and corresponding separation of the parts, thereby permittingthe boot and ski to move relative to one another the extent necessary toprevent injury.

In a preferred embodiment of the invention, two connecting units aremounted on the soleplate, one associated with the heel end of the bootand the other with the toe end. The heel unit is disposed in upstandingrelationship at the rearward end of the soleplate and has its leashconnected to the associated mounting element which is fixed on the skiat a location just rearwardly of the boot heel. The toe unit is carriedon the underside of the soleplate about midway between the ends of thesoleplate and connects to its mounting element at a locationcorresponding approximately to the ball of the foot when the boot is inplace. When the leashes are fully retracted under the influence of therespective biasing means, here comprising single springs, the soleplateengages the mounting elements which additionally serve as guides toinsure that the soleplate is in proper alignment on the ski when inskiing position and to alter the level of externally applied forcesrequired to cause the leashes to extend depending upon the direction inwhich the force is applied.

It is significant that with this cooperative arrangement of engagingparts of the soleplate and mounting elements, the force levels at whichseparation occurs, so as to prevent injury, are not affected byconditions encountered in use, including flexural distortion of the skiwhich, in turn, results in the mounting elements moving somewhatrelative to one another.

A further aspect of the invention resides in the con struction andarrangement of each connecting unit which enables tension-displacementprofiles to be programed as desired throughout the range of extension ofthe leash, including the skiing phase and the release phase, and for themaximum tension force to be accurately adjusted to the desired level.Each connecting unit has its leash wound at least partially on a supportmember mounted for rotation within a housing. and the terminal end ofthe leash secured to its associated mounting element. The leash, at itspoint of separation from the support member, is spaced from the axis ofrotation of the support member by a radial distance defined as a leashmoment arm. Force applied to the leash to extend its exerts an unwindingtorque on the support member, and the biasing spring applies a biasingforce to the support member to resist rotation at a radial distance fromits axis of rotation defined as a biasing moment arm. A ratio deviceprogressively increases the ratio of the leash moment arm to the biasingmoment arm as the leash is unwound, thereby progressively decreasing theforce necessary to release the leash as relative separation of thesecond members increases.

By suitable configuration of the ratio device, the tension-displacementprofile of the leash is programmed as desired and may be considered foranalysis as divided into the initial skiing phase and the subsequentrelease phase. The skiing phase, which prevails prior to and duringinitial separation, commences at a substantial tension value sufficientto hold the ski firmly against the ski boot, but drops off at apreselected rate, which can be programmed as desired, during initialseparation. In the release phase, the tension has dropped considerably,and such phase continues over sufficient dis tance to permit thesoleplate and ski to move relatively freely, yet remain in leashedrelationship. In an extreme final phase of extension the leash momentarm commences to decrease again and the force returns to another maximumvalue, giving a shock absorbing effect just prior to complete extension.

Once the forces causing separation have dropped to safe levels, theleash is retracted automatically, and the unit ultimately shifts back toits skiing phase to restore the high tension force on the leash, therebydrawing the boot and ski back into and holding them in skiingrelationship.

The soleplate and the heel and toe mounting elements on which it rests,are provided with cooperative self-aligning mating surfaces so that asthe soleplate is pulled back onto the mounting elements by the leashesduring the final phase of restoring action of the connecting units, theski boot is automatically returned to the normal skiing position on theski. For this purpose, the soleplate in its rear region and the heelmounting element are provided with complementary, V- configurationmating surfaces positioned symmetrically on opposite sides of thecenterline of the ski parallel thereto. The soleplate carries a cammingmember which engages a rearwardly projecting, swiveling lug extendingfrom the rear end of the forward mounting element. The load bearingupper surface of the toe mounting element is spaced above the lug so asnot to impede its swiveling action to align with the centerline of theski under the influence of the leash from the toe unit, which isconnected to the lug. To reduce lateral friction between the forwardmounting element and the underside of the soleplate, a suitableanti-friction means, such as a layer of low friction material, ismounted on at least one of the soleplate and the upper surface of thetoe mounting element.

Other features and advantages of a ski binding constructed in accordancewith the preferred embodiment of the invention will become apparent fromthe following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS A ski binding according to certainpreferred embodiments of the invention is illustrated in theaccompanying drawings in which:

FIG. 1 is a perspective view ofa ski boot mounted on a portion ofa skiby a ski binding constructed in accordance with a preferred embodimentof the invention and in a skiing phase of operation, the boot and theski being shown disposed in a normal skiing relationship;

FIG. 2 is a perspective view of the ski binding shown in FIG. 1, butwith the ski boot separated from the ski in a release phase of operationof the ski binding;

FIG. 3 is a side view, partially in crosssection. of the ski bindingshown in FIG. I;

FIG. 4 is a plan view of a soleplate which underlies the ski boot andforms a part of the ski binding according to the present invention andwhich carries the operative mechanism of the binding;

FIG. 5 is a cross-sectional side view on an enlarged scale of a portionof the soleplate shown in FIG. 4 taken along the lines 5-5 therein,showing a toggle mechanism for releasably clamping the toe end of theski boot to the soleplate;

FIG. 6 is a perspective view of the binding, with certain portionsremoved for clarity, and an underlying portion of the ski, the bindingand ski being shown in separated condition;

FIG. 7 is a perspective view of portions of the ski binding for selfcentering the toe region thereof, shown in the released condition;

FIG. 7a is a cross-sectional side view of the portions of the skibinding shown in FIG. 7 but in an engaged condition;

FIG. 8 is a cross-sectional end view of the soleplate shown in FIG. 6taken along the lines 8--8 therein;

FIG. 9 is a cross-sectional view of a portion of a heel mounting elementforming a part of the ski binding shown in FIG. 6, the section beingtaken along the lines 9-9 therein;

FIG. 10 is a side view, partially in cross-section, and on an enlargedscale, of a rear end portion of the ski binding shown in FIG. 3, showinga heel connecting unit forming a part of the ski binding according tothe invention; 1

FIG. 11 is a cross-sectional end view of the rear leash unit shown inFIG. it) taken along the lines ll--II therein;

FIG. 12 is a cross-sectional end view similar to FIG. 11, but takenalong the lines 12-12 of FIG. 10.

FIG. 13 is a fragmentary sectional view of a adjustment mechanismsimilar to that shown in the upper portion of FIG. 12, but operativeover a lower load range, for adjusting the maximum tension applied tothe leash by the heel connection leash unit, which forms a part of thepresent invention;

FIG. 14 is a view similar to FIG. 13 of another adjustment mechanismoperative over a still lower load range;

FIG. 15 is a graphical representation of the forcedisplacement curve ofone of the connecting units forming a part of the present invention;

FIG. 16 is a cross-sectional view of an alternative embodiment of theconnecting unit; and

FIG. 17 is a cross-sectional side view of the leash unit shown in FIG.16 taken along the lines I7-I7 therein.

DETAILED DESCRIPTION A ski binding according to the invention (FIGS. 1and 2) is intended to support a ski boot 20 on an underlying ski 22 ingeneral alignment with the ski in a normal skiing position. The ski boot20 is mounted on a rigid soleplate 24 by rear and forward clamps 26 and28, respectively, engaging the heel and toe of the ski boot. Thesoleplate rests on forward and rear, or toe and heel, mounting elements30 and 32 secured to the ski and is held against them by flexibleleashes 34 and 36 which form part of forward and rear connecting units38 and 40, respectively, carried by the soleplate.

In the event of an abnormally high force acting to separate the skiersboot from the ski, the soleplate 24 separates from the mounting elements30 and 32 to release the ski boot from the ski, thereby minimizing thechance of injuries which may otherwise occur under such skiingconditions. The connecting units 38 and 40, sometimes referred to asleash units, are so constructed that, while the soleplate is engaged andduring initial separation, the leashes exert a very substantial tension(for example, 200 lbs. or so) so that minor and short lived shocks thatoccur during skiing do not cause the soleplate to separate from the ski.However once the preselected tension is exceeded, separation of thesoleplate from the mounting elements commences. During furtherseparation, the tension necessary to extend the leashes decreasesrapidly so that the ski thereafter separates readily from the soleplate.Once the application of the abnormal force ceases, the soleplate ismoved back towards the ski by the leashes and as soon as it reachesclose proximity to the mounting elements 30 and 32 the tension forceexerted on the leashes 34 and 36 again rises to a high level clampingthe soleplate firmly back onto the mounting elements with a selfaligning action to restore the ski boot to the normal skiing position.

The soleplate 24 (FIGS. 3, 4 and 6) includes a main body 42 having aflat horizontal lower wall in underlying contact with the sole of theski boot. Vertical flanges may be provided along the edges of thesoleplate to provide additional stiffening. Two hollow girders 44 (FIG.6) are mounted on the flanges of the main body 42 extending rearwardlyfrom it. The rearward extremities of the girders 44 support atransversely extending heel plate 46 positioned to underlie the heel ofthe ski boot 20. The position of the heel plate 46 in relation to themain body 42 can be adjusted, to accommodate ski boots of differentsizes, by releasing set screws 48 which permit the girders 44 to be slidforwardly and rearwardly (FIG. 8). A vertical rear wall 50 (FIGS. 3 and6) is secured to the rear end of the girders 44 and to the heel plate 46and carries the previously mentioned heel clamp 26 for clamping the heelof the ski boot 20.

The heel mounting element 32 is provided with two longitudinallyextending, spaced parallel ribs 52 (FIG. 6) inclined upwardly andinwardly in generally V- shaped configuration to cooperate withcomplemen tary V-shaped mating surfaces 54 (FIG. 11) formed on theunderside of the heel plate 46. As the leash 36 draws the heel plate 46into contact with the heel mounting element 32, the complementaryV-shaped mating surfaces exert a self-centering action positioning theheel plate centrally of the ski while permitting sufficient longitudinalmovement to avoid pinching and to enable the forward end of thesoleplate to align itself with the toe mounting element 30 (as will bedescribed).

To align the forward end of the soleplate with the ski. a camming member(FIGS. 7 and 7a) is secured to the underside of the main body 42 of thesoleplate extending transversely of it. The camming member 60 includes adownwardly and forwardly inclined upper leading edge 6] which isoverlapped and abutted by a rearwardly projecting lug 62. The lug 62 ismounted for pivoting motion about a vertical pivot shaft 64 projectingfrom the front mounting element 30 and positioned on the longitudinalcenterline of the ski. The forward end of the leash 34 is secured to thelug 62 which is thereby pulled into alignment with the centerline of theski. The cooperating surfaces of the camming member 60 and the lug 62are arcuately curved in symmetrical disposition about the centerline ofthe ski so that they function as cam surfaces exerting a self-centeringaction on the camming member 60 as it moves into contact with the lug 62under the tension exerted by the forward leash 34. To assist the cammingmember 60 in clearing the lug 62 as it moves downwardly during restoringaction after separation, the rear wall 50 is at a slight forwardinclination to the vertical. Thus the rear leash exerts a rearwardcomponent of force which pulls the camming member back sufficiently toclear the lug 62. On continued downward motion as the forward leashrises to the high force level in the skiing phase, the forward leashovercomes the rearward force component of the rear leash so that thecamming member 60 is then pulled forwardly into the abutting,overlapping position against the lug.

It will be appreciated that the V-shaped cooperating surfaces on theheel plate 46 and the rear mounting element 32, and the arcuatecooperating surfaces on the camming member 60 and the lug 62 secured tothe forward mounting element 30 provide the soleplate 24 with acapability for self aligning with the longitudinal centerline of the skias it is drawn toward the mounting elements under the influence of theleashes 34 and 36, thus automatically restoring the ski boot to thenormal skiing position on the ski. In addition the lug 62 and cammingmember 60 establish the longitudinal position of the ski boot on theski.

It is desirable for both safety and performance reasons to have thebinding initially permit relative lateral movement between the boot andski in response to externally applied lateral forces of lower magnitudethan those required to produce relative movement normal to the surfaceof the ski. For example, considering the toe end of the boot andassuming that the soleplate 24 is on the ski at proper alignmenttherewith so that the leash 34 is fully retracted and there is maximumresistance to movement, it is desired that a substantially lower forceapplied laterally, i.e., a twisting force on the foot or leg,

initiate relative movement than would be required in order to lift thetoe vertically away from the surface of the ski. This desirable resultis achieved by the foregoing structure and in particular by theoverlapping relation of the lug 62 to the camming member 60. Because ofthe forwardly and downwardly slope of the edge 61 of the camming member(FIG. 7a) bearing against the underside of the lug 62, upward force onthe soleplate at the toe will cause the camming member to sliderearwardly until it clears the lug. Such rearward motion is opposed bythe forward leash 34. Lateral horizontal motion of the soleplate at thetoe will also require extension of the forward leash. By suitable choiceof the angle of inclination of the forward edge 61 of the cammingmember, it is arranged that the upward force necessary to free the toeof the boot for upward movement is several times (approximately threetimes in the preferred embodiment although higher multiples may be usedfor expert skiers) the force necessary to enable lateral, horizontalmovement of the boot at the toe.

The load bearing surface of the front element 30 supporting the weightof the soleplate projects vertically above the lug 62 so as not toimpede its pivoting move ment. A layer of friction resistant material 66(FIG. 6), such as polytetrafluoroethylene, which is sold under thetrademark Teflon, is mounted on the load hear ing surface of the frontmounting 30 to facilitate lateral rotational motion of the soleplateduring its selfalignment with the front and rear mounting elements 30and 32. Other anti-friction devices, for example rollers, mayalternatively be mounted between the soleplate and the toe mountingelement, secured to either, to reduce lateral friction.

The previously mentioned rear connecting unit 40 (FIGS. 10-12) includesa generally rectangular box-like housing 70. Within the housing is arotary device supporting the leash, which includes a rotor 72 mountedfor rotation about a central axle 74. The leash 36 rests on one side ofthe rotor 72 and is wound about the periphery of a kidneyshaped leashsupport member 76 extending from the surface of the rotor 72 andintegral with it. The opposite side of the rotor is provided with anannular boss 78 having a slot 80 at one point in its periphery. Aninternal bearing 81, concentric with the axle, supports the boss 78. Atorsion spring 82 has one of its ends anchored in the slot 80 and itsother end anchored in a slot 84 in the wall of the housing 70. Thedirection of biasing force exerted by the tension spring 82 is such asto urge the rotor 72 in a direction to wind the leash 36 inwardly of thehousing 70 and about the periphery of the leash support member 76.

The point at which the leash 36 tangentially leaves the leash supportmember 76 is spaced from the axis of rotation of the leash supportmember by a radial distance defined as the leash moment arm d (FIG. 11).Similarly, the point at which the force supplied by the biasing spring82 is applied to the boss 78 is spaced from the axis of rotation of theleash support member by a radial distance defined as the biasing momentarm D (FIG. 12). In the fully secured position (shown in FIG. 11) inwhich the heel plate 46 is resting in contact with the rear supportelement 32, the ratio of the leash moment arm to the biasing moment arm(Le. dzD) is at a minimum and the tension force that must be supplied tothe leash 36 to overcome the biasing spring force is therefore at amaximum value. For example, in a preferred embodiment, a force ofapproximately 200 lbs.

must be applied to the leash 36 of the rear connecting unit 40 toinitially overcome the biasing spring in the fully secured position.When a force of the requisite magnitude is applied to the leash, thebiasing torque exerted by the spring is overcome and the leash supportmember 76 rotates within the housing in a direction such as to unwindthe leash permitting it to pay out through the opening 71 so that theheel plate 46 can separate from the mounting element 32.

Considering the leash member 76 after it has rotated to the dotted lineposition shown in FIG. 11, it will be seen that the leash moment arm (1has increased to d while the biasing moment arm D has remainedunchanged. Thus the ratio of the leash moment arm to the biasing momentarm has progressively increased relative to its initial value so thatthe force which must be applied to the leash to overcome the biasingtorque is progressively reduced. By routine mathematical calculations,the peripheral configuration of the generally kidney-shaped leashsupport member 76 can be chosen to give a force-displacement profilecorresponding to that shown in FIG. 15.

As shown in FIG. 15, a substantial force is necessary to cause initialseparation of the soleplate from the mounting element and during aninitial, or skiing phase, the rate of decline of force with increaseddisplacement is very rapid. Thereafter, separation enters a releasephase in which the force has dropped to a residual value several timeslower than the initial value and little further change occurs duringcontinuing separation. In a final phase, just prior to completeextension as the last portion of the leash unwinds from the kidneyshapedleash support member 76, the configuration thereof is such that theleash moment arm d" starts to decrease to a minimal value so that theforce profile commences to increase again. The result is to provide ashock absorbing effect in the final region of leash travel before theleash is fully paid out. Although the terms skiing phase, release phaseand final phase have been used for convenience to describe the threemain modes of operation, it will be understood that the phases need notbe sharply defined from each other but may merge without any substantialvariation in the rate of change from one phase to the next.

The described force profile avoids imposing continued large loads on theboot (and the skiers ankle) once separation has become inevitable. Afterthe abnormal force tending to separate the ski from the ski boot hasceased to act, the biasing spring 82 urges the leash support member 76in a reverse rotational direction to rewind the leash onto the leashsupport member 76, following back along the force profile shown in FIG.15.

On occasion during skiing situations the ski boot may separate from theski under the action of abnormal forces, passing through the skiingphase and into the release phase, and be automatically restored backthrough the skiing phase to the fully connected position after theabnormal force has abated, without the skier ever losing control.

Skiers of different competence from beginner through intermediate toadvanced and those of different physical characteristics requiredifferent initial release forces. To adjust the leash unit so that ithas a variable initial force required for release, mechanism is provided(FIGS. l2l4) for adjusting the initial rotational position of the leashsupport member 76 to vary the initial value of the leash moment arm (1.The mechanism includes an arcuate flange 86 projecting from theperiphery of the rotor 72 on the same side as the boss 78. A leadingedge of the flange 86 (leading in the direction of winding rotationcaused by the spring 82) abuts an adjustable stop 88 mounted on thehousing 70. The stop 88 includes an arcuate guide member 90 slidablyabutting the exterior of the flange 86, which is mounted in acorrespondingly configured channel 92 in a block 94 mounted in thehousing 70. The guide member 90 has a central slot 96 limiting the rangeof arcuate travel of the guide member 90 in relation to a pin 98 fixedto the block 94. A flexible adjusting pin 100 bearing against one end ofthe guide member 90 can be moved in and out by a set screw 102 to finelyadjust the position of the guide member 90. The guide member 90 includesa shoulder portion 104 which abuts against the leading edge of theflange on the rotor. Adjustment is made as follows: For a beginner, itis desired to set the leash moment arm d at a value which will permitseparation at a relatively lower initial force, for example say 100 lbs.Thus a guide member 90 will be provided (FIG. 14) wherein the shoulderportion 104 is relatively long in relation to the overall length of theguide member 90 so that the leading edge of the flange 86 is displacedby a maximum initial amount to provide a relatively large initial leashmoment arm d. Fine adjustment of the precise position of the leadingedge of the flange can be set by adjusting the set screw 102 so that thepin 100 urges the guide member 90 to a precise position of adjustment.However the length of the slot 96 in relation to the pin 98 is such asto limit the maximum range of adjustment of the guide member 90 so thatat either extreme position the initial release tension is still withinacceptable limits for the characteristics of a particular skier. For anintermediate skier, the shoulder portion 104 does not comprise such agreat proportion of the length of the guide member 90 compared to thatfor the beginner so that the degree of prerotation of the leash supportmember 76 is somewhat less (FIG. 13). For an advanced skier, the stopmember 104 is a minimum proportion of the overall length of the guidemember 90 and is such that the initial value of the leash moment arm dis at a minimum value as shown in FIG. 11.

Adjustment of the initial level of tension for release may also be madeby adjusting the peripheral position at which the bias spring 82connects with the boss 78 (FIG. 12). For this purpose additional notchedopenings, 105, 106 and 107 are provided in the boss to alternativelyreceive the end of the bias spring 82.

To form a seal preventing ingress of foreign matter through the opening71 of the housing, an O-ring 110 is mounted in the throat of the opening71. The surfaces of the opening extending on either side of the O- ring110 are flared away in both the horizontal and vertical planes to avoidchafing the leash in its passage in and out of the housing 70. The innerend of the leash 36 is provided with an enlargement 112 which seats inan opening 114 in the leash support member 76. At its opposite endoutside the housing, the leash member 36 is provided with a ball 116(FIG. 9) which is seated within a hollow nut 118 threadedly mounted in abaseplate 120. The baseplate 120 is shaped to seat between the arms 52(FIG. 11) of the previously mentioned rear mounting element. The preciselongitudinal position of the base 120 in relation to the rear mountingelement 32 can be controlled by sliding the baseplate 120 longi- 10tudinally and then locking it in position by means of a set screw 122(FIG. 6). By making the shank on the threaded nut I18 sufficiently long,it can be provided with a range of vertical adjustment allowing it totake up any slack in the leash 36 when the units are calibrated in theinitially secured condition.

The housing is secured to the rear wall 50 by suitable boltedconnections 123 (FIG. 11). The bolted connections 123 ride in verticalslots in the rear wall to allow for initial vertical adjustment of therear leash unit 40.

The previously mentioned toe connecting unit 38 (FIGS. 2-4 and 6) is ofthe same construction as the rear leash unit 40 but is mountedhorizontally on the underside of the main body member 42 of thesoleplate 24. However the initial leash tension for release for thefront connecting unit may be set at a lower value than for the rearconnecting unit. The leash 34 of the forward leash unit 38 projectsforwardly through a V- shaped opening 124 (FIG. 4) in the previouslymentioned camming member 60 and is secured to an anchoring block 125(FIGS. 7 and 7a) mounted in a complementary slot in the rear edge of thelug 62. The anchoring block includes a vertical and longitudinallyanchored bore 126 into which the forward end of the leash 30 is securedby soldering or the like. A horizontal transverse pin connects theanchoring block to the lug 62 for vertical pivoting motion. Thisarrangement enables the block 125 to align itself with the direction inwhich the leash is pulling and avoids the development of an abrupt bendin the leash in the lug region. In addition the leash and anchoringblock assist in guid ing the connecting member 60 back into matingrelation with the lug during the restoring action that followsseparation.

The housing of the forward connecting unit 38 is secured to thesoleplate by bolts 125 (FIG. 4) riding in longitudinally elongated slotsin the soleplate 24. To adjust the position of the connecting unit 38longitudinally the bolts 125 are slackened off and set screws 126, whichextend through the camming member 60 into abutting contact with thehousing of the unit 38 and act against the leash force, are screwed inor out as required. The bolts 125 are retightened once the desiredadjustment has been made.

It will be appreciated that the soleplate 24 is held on the forward andrear mounting elements 30 and 32 only by the leashes 34 and 36. Furtherif the ski should flex longitudinally tending to move the forward andrear mounting elements 30 and 32 relatively towards each other, thiswill not cause a pinching effect tending to hold the soleplate grippedbetween the mounting elements which would impair release because therear mounting element 32 permits sliding motion of the heel plate 46.Thus, even when the ski is flexing to move the mounting elementsrelatively toward each other, the ability of the soleplate to separateis not impaired. The mounting of both connecting units on the soleplate,therefore, offers significant advantages over an arrangement wherein theconnecting units are mounted directly on the ski and pinching can occur.

The foregoing arrangement whereby the soleplate is attached to the skiat two spaced apart points with sliding motion permitted between one ofthe mounting elements and the soleplate, has been found to yield a greatimprovement in the performance of the ski itself. As a consequence ofthat arrangement the ski is free to flex along its full running lengthinstead of having a flat spot in the region of the ski boot which occurswith a fixed ski binding. As a result ski control and turningperformance of the ski are improved to a very noticeable degree.

An alternative embodiment of the leash unit is shown in FIGS. 16 and I7.In this construction. a housing 131 of generally rectangularconfiguration has within it a leash support member 132 of circularconfiguration mounted for rotation on an axle I33. A leash I34 woundabout the periphery of the leash support member passes outwardly of thehousing in a similar manner to that previously described. Because of thecircular configuration of the leash support member 132 it will beappreciated that the leash moment arm d remains at a substantiallyconstant value equal to the radius of the leash support member from thecenter of the axle 133. A second axle I35 disposed in spaced parallelrelation to the first axle 133, is acted on by a torsion spring I36having one of its ends connected to a peripheral slot 1370 in the axleI35 and its opposite end connected to the housing 131. Secured to thefirst axle 133 is a noncircular gear sector 138 which meshes withanother noncircular gear sector I39 secured to the second axle I35. Whenthe leash 134 is in a fully would condition on the leash support member132, so that the leash support unit is connecting the soleplate to theadjacent one of the mounting elements in the fully secured condition,the point of meshing contact between the gear sectors I38 and I39 is ata maximum distance from the axle I33, corresponding to a maximumdimension of the biasing moment arm D (FIG. 16). The spring I36 acts ina direction to cause tension to be applied via the gear train to theleash in a direction inwardly of the housing. As sufficient outwardtension is applied to the leash to overcome the biasing force and rotatethe leash support member in a direction to unwind the leash, the pointof meshing contact between the gear sectors 138 and 139 moves towardsthe axle of the leash support member thereby reducing the biasing momentarm D". Thus, the ratio of the leash moment arm d (which remainsconstant) to the biasing moment arm D (which is progressively reducing)increases and the tension necessary to overcome the biasing spring 136is progressively reduced. By suitable choice of the gear profiles I38and 139, a force-displacement profile corresponding to that shown inFIG. can be achieved.

The gear sectors I38 and 139 thus constitute a ratio changing device forchanging the ratio of the leash moment arm to the biasing moment arm ina comparable manner to that in which the kidney-shaped configuration ofthe leash support member in the first embodiment also functions as aratio changing device. The difference is that in the preferredembodiment there is a constant biasing moment arm and an increasingleash moment arm while in the second embodiment there is a constantleash moment arm and a reducing biasing moment arm.

To enable the value of initial tension necessary for release to bechanged for skiers of different skill or physical characteristics, theshaft 135 is provided with alternative openings 137b, l37c and 137d intowhich the end of the spring 136 may be slotted. In addition anadjustment mechanism 140 of the type shown in FIGS. 13 and 14 previouslydiscussed, may also be incorporated in the second embodiment foradjusting the level of initial tension of the leash.

The previously mentioned heel clamp 26 for securing the heel of the skiboot 20 to the soleplate, comprises a generally rectangular.transversely extending body 141 (FIG. 6) having two vertical channels142 formed in its rear surface to engage correspondingly shaped verticalribs 144 provided on the forward face of the rear wall 50. The ribs 144guide the body 141 for vertical movement and stabilize it. The body 141may be clamped in any vertical position of adjustment by threadedconnectors 146 (FIG. 3) which extend through the rear wall 50. Mountedon the body I4] projecting forwardly from it are two arcuatelyconfigured arms 148 (FIG. 4) shaped to embrace the heel of the ski boot20 and overlie the upper surface of a rearwardly projecting portion ofthe heel. The heel plate 46 includes a lip 150. The ski boot is coupledto the soleplate by positioning the rear upper edge of the heel in placebeneath the arms I48 of the block with the sole canted upwardly. Theboot is then pivoted downwardly about the lip 150 to bring the upperhorizontal rim of the heel into forceful engagement with the arms 148.

Thereafter, the previously mentioned toe clamp 28 is operated. The toeclamp 28 includes a curved arm 154 (FIG. 15) connected at its lower endto the upper surface of the soleplate for vertical pivoting motion abouta horizontal transverse pivot axis. A torsion spring 156 is mountedbetween the arm I54 and an adjacent post 158 to urge the arm 154upwardly to a released condition. At its rearward end, the arm 154 isflared laterally in either direction and provided with an internalarcuate curve so that it can engage the upper surface of the peripheraledge of the sole of the ski boot 20. The arm is provided with anindentation 160 in its upper surface into which a ski pole can be placedto move the arm 154 downwardly into engagement with the ski boot 20. Tolatch the arm 154 in the down position against the ski boot, a swinginglatch 162 is also pivotally connected with the soleplate and is inclinedupwardly and forwardly passing through an opening 164 in the arm. Thelatch 162 includes a shoulder 166 which abuts against the adjacentshoulder 168 formed in the arm 154 to latch the arm in the downposition. A torsion spring 170 is connected between the latch 162 andthe post 158 to urge the latch to the latched position. At its upper endthe latch 162 is provided with an indentation 172 into which the tip ofa ski pole may be placed so that the latch 172 can be pushed downwardlyreleasing the arm 154 which swings upwardly under the influence of thespring 156 to release the front end of the ski boot. The upper surfaceof the latch 162 in the region of the indentation 172 is provided withan inclined camming surface to enable it to slide readily through theopening 164 in the arm 154 as the arm is moved downwardly to the lockedcondition.

A lock out mechanism (FIG. 12) is provided in the rear connecting unit40 to facilitate working on the device with the soleplate in thereleased position, as may need to be done from time to time foradjustment purposes. The lock out mechanism includes a detent pin I74mounted in the housing 70 for radial motion towards the periphery of therotor 72, against the action of a biasing spring 176. A notch 178 in theperiphery of the rotor 72 moves into alignment with the pin 176 when theleash is fully extended. To use the lock out mechanism, the leash ispulled to the fully extended position, the pin 174 is pushed in, and theleash is released so that the edge of the notch moves with contact withthe pin 174 holding it frictionally against release under the influenceof the spring 176. To release the leash, tension is applied to it,releasing the sideward frictional force on the pin 174 so that thespring 176 moves it out of the way, after which the biasing springreturns the rotor 72 and the leash to the retracted position. A similarlock out mechanism is provided for the front connecting unit 38.

Summarizing, the present invention provides a ski binding which canseparate the ski boot from the ski to avoid injury during moments ofabnormal application of force tending to separate the ski boot from theski and which automatically restores the ski boot to skiing position onthe ski once the abnormal force has terminated. Moreover, by mountingthe connecting units on the soleplate rather than on the ski the ski isfreed for flexing movement along its whole length thereby improving skiperformance, while at the same time the ability of the ski boot toseparate under the influence of abnormal force remains unimpaired. Theconnecting units themselves have the capability of requiring asubstantial force before initial release and in the skiing phase andthereafter allowing separation at a much lower level of force in thesubsequent release phase, utilizing only a single biasing spring.

Although the invention has been described with reference to certainpreferred embodiments, it will be understood by those skilled in the artthat many modifications, deletions, substitutions and other changes maybe made which would be within the obvious purview of one skilled in theart without departing from the spirit of the invention.

We claim:

1. A ski binding coupling a ski boot on a ski and releasably holding itin alignment therewith in a normal skiing position, the bindingcomprising:

a soleplate arranged for positioning in underlying contact with the skiboot and for detachable connection thereto;

at least one mounting element secured to the ski, said mounting elementbeing proximate said soleplate when the ski boot is in such skiingposition;

at least one connecting means carried by said soleplate for connectingsaid soleplate to said mounting element, said connecting meansincluding:

a leash support on said soleplate;

an elongated, flexible leash supported at least partially on said leashsupport and connected with said mounting element, said leash beingextendible and retractable from said leash support to permit saidsoleplate and mounting element to move toward and away from one anotherand being in a retracted condition when said mounting element isproximate said soleplate; and

biasing means on said soleplate acting on said leash and including meansfor applying a retraction force to said leash to resist separation ofsaid soleplate from said position proximate said mounting element andcontrol means for varying the effectiveness with which said retractionforce is applied, said biasing means being responsive to a force, actingthrough said leash and tending to separate said soleplate from saidmounting element, in excess of a predetermined magnitude to permit saidleash to extend from its retracted condition and said soleplate to moveout of such skiing position and, thereafter, being responsive toreduction of such separating force to a magnitude below the retractionforce being then applied to said leash to initiate retraction of saidleash toward its retracted condition and to continue such retraction solong as the separating force is below the retraction force being thenapplied to said leash, until said leash returns to its retractedcondition.

2. A ski binding as defined in claim 1 wherein said biasing meansfunctions in two phases of operation, including a skiing phase in whichthe tension exerted on said leash is at a high level prior to initialseparation and, thereafter, decreases progressively at a rapid rate, anda release phase following separation over said initial range in whichthe tension exerted on said leash by said biasing means is at arelatively lower level.

3. A ski binding as in claim 1 wherein said soleplate and mountingelement include cooperative guiding means engageable to aid in aligningsaid soleplate with respect to said ski and in establishing its positionlongitudinally thereof when said leash is fully retracted to positionthe boot in skiing position.

4. A ski binding as in claim 1 further including adjustment means onsaid leash support operatively associated with said biasing means forvarying the tension exerted on said leash when said leash is retracted.

5. A ski binding as in claim 4 wherein the tension force exerted on saidleash by said biasing means is maximum when said leash is retracted.

6. A ski binding as in claim I wherein said connecting means is operableautomatically upon extension of said leash and after the forces causingsuch extension have abated, to retract the same.

7. A ski binding comprising:

boot-engaging means adapted for connection to a ski boot;

a mounting element secured to the ski;

connecting means carried by one of said bootengaging means and mountingelement and extending therebetween to serve as a force-applying link,said connecting means comprising:

a housing;

a support member on said housing and mounted for rotation relativethereto about an axis of rotation;

a leash wound at least partially around said support member and arrangedto be extended and retracted during rotation thereof, said leash at itspoint of separation from said support member being spaced from said axisof rotation by a radial distance defined as a leash moment arm;

means for applying a biasing force to said support member at a radialdistance from the axis of rotation thereof defined as a biasing momentarm, said biasing means acting to apply a torque to said support memberin a direction to wind said leash onto said support member and therebyretract said leash; and

ratio means increasing the ratio of said leash moment arm to saidbiasing moment arm as said support member rotates in a direction toextend said leash, thereby decreasing the force required to producefurther extension thereof.

8. A ski binding as defined in claim 7 wherein said biasing meanscomprises a single spring connected with said housing and with saidsupport member.

9. A ski binding as defined in claim 7 including adjustment means onsaid housing and operatively associated with said ratio means foradjustably establishing the initial ratio of said leash moment arm tosaid biasing moment arm.

10. A ski binding as defined in claim 9 wherein said leash moment armremains substantially constant and said biasing moment arm varies duringrotation of said support member.

ll. A ski binding as defined in claim 9 wherein said biasing moment armremains substantially constant and said leash moment arm varies duringrotation of said support member.

12. A ski binding as defined in claim 7 wherein said ratio is minimumwhen the leash is fully retracted and progressively increases during atleast an intial portion of such leash extension and, thereafter, remainssubstantially constant during a further portion of such leash extension.

13. A ski bonding coupling a ski boot on a ski and releasably holding itin alignment therewith in a normal skiing position, the bindingcomprising:

a soleplate extending in underlying contact with the ski boot andconnected thereto;

heel and toe mounting elements secured to the upper surface of the skiat locations spaced longitudinally thereof, said elements underlying andsupporting said soleplate in the normal skiing position;

heel and toe connecting means carried by said soleplate and extendingbetween and serving as the force-applying links between said soleplateand said mounting elements, each of said connecting means including:

a support fixed on said soleplate;

a rotatable device mounted on said support for rotation relativethereto;

a flexible leash substantially longer than the spacing between adjacentportions of said soleplate and said elements in said skiing position,said leash being wound at least partially on said rotatable device andbeing extended and retracted during rotation thereof to permit saidsoleplate to move out of and back into said skiing position; and

biasing means on said support including means for urging said rotatabledevice to rotate in a direction to retract said leash and apply atension force thereto and means for controlling the magnitude of saidtension force as a function of the extent of leash extension from arelatively high level when said leash is retracted to a reduced levelduring extension thereof.

14. A ski binding as in claim 13 wherein the tension force on said leashis maximum when said leash is fully retracted and said soleplate is innormal skiing position, progressively reduces rapidly during initialextension thereof and remains substantially constant during furtherextension.

15. A ski binding as in claim 13 wherein said heel connecting means iscarried in generally upstanding orientation at the heel end of saidsoleplate with its respective leash extending generally vertically downwardly from its respective rotatable device to said heel mountingelement when said soleplate is in the normal skiing position.

16. A ski binding as in claim 13 wherein said toe con necting means iscarried in a generally horizontal orientation on the underside of saidsoleplate with its respective leash extending generally horizontallyfrom its respective rotatable device to said toe mounting element whensaid soleplate is in the normal skiing position.

17. A ski binding as in claim 13 wherein said soleplate and said toemounting element are formed with mating cam surfaces which engage whensaid leash of said toe connecting means is retracted to center saidsoleplate relative to the ski and thereby establish the normal skiingposition.

18. A ski binding as in claim 17 wherein said forward mounting elementincludes a pivotal lug that receives the end of said leash of said toeconnecting means and is formed with one of said mating cam surfaces; and

wherein said mating cam surfaces engage to prevent forward slidingmovement of said soleplate longitudinally of the ski but permit lateraland rearward movement relative to said ski.

19. A ski binding as defined in claim 13 further including:

heel guide means on said heel mounting element and on said soleplate toself-align said soleplate with the longitudinal centerline of the skiwhen said soleplate is drawn into contact with said heel mountingelement; and

toe guide means on said toe mounting element and on said soleplate toselfalign said soleplate with the longitudinal centerline of the skiwhen said soleplate is drawn into contact with said toe mountingelement.

20. A ski binding as defined in claim 19 wherein one of said heel andtoe guide means permits longitudinal sliding motion of the adjacentsurfaces of the soleplate and mounting element and the other preventssuch longitudinal sliding motion in at least one direction.

21. A ski binding as defined in claim 7, wherein said means for applyinga biasing force includes,

an axle connected with said housing for rotation about a second axis ofrotation parallel to the axis of rotation of said support member spacedtherefrom,

torque means for applying torque to said second axle,

and wherein said ratio means includes first and second, non-circulargear members connected to said support member and said axle in meshingengagement, the distance between the point of meshing engagement of saidgears and said axis of rotation of said support member defining saidbiasing moment arm, said gears being configured to move their point ofmeshing engagement progressively closer to the axis of rotation of saidsupport member as said support member rotates in a direction to uncoilsaid leash, thereby progressively reducing said biasing moment arm.

22. A ski binding as defined in claim 12 wherein said ratioprogressively decreases to another minimum value during a final portionof such leash extension following said further portion of such leashextension.

23. A ski binding as defined in claim 14 wherein the tension force onsaid leash progressively increases to another maximum value during afinal increasing portion of leash extension following said furtherportion of leash extension.

24. A ski binding coupling a ski boot on a ski and releasably holding itin alignment therewith in a normal skiing position, the bindingcomprising:

a soleplate arranged for positioning in underlying contact with the skiboot and for detachable connection thereto, said soleplate being movableinto and out of normal skiing position;

cooperating guides on said soleplate and mountable on said ski andlocated in underlying relationship with the soleplate when the latter isin a normal skiing position, said guides engaging as said soleplatemoves into such normal skiing position to aid in aligning said soleplaterelative to the ski; and

connecting means secured to and carried by said soleplate, saidconnecting means including:

a force-applying link connected to the ski, said link being movablerelative to the said soleplate to comprises an elongated, flexibleleash.

t 1F I 1' I UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OFCORRECTION PATENT NO. 3,893,682

DATED July 8, 1975 INVENTOR( I Burton A. Weinstein and Gordon C. Lipe Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 1, line 12, "safetytype" should read safety-type Column 3, line18, "its" should read it Column 4, line 24, "crossection" should readcross-section Column 7, line 40, "kidneyshaped" should readkidney-shaped Column ll,line 25 "would" should read wound Column 15,Claim 13, line 20, "bonding" should read bindinq Sigurd and Sealed thisThirteenth Day Of June 1978 [SEAL] Attest:

D NALD W. RUTH C. MASON O BANNER Attesting Ojficer Commissioner ofPatents and Trademarks

1. A ski binding coupling a ski boot on a ski and releasably holding itin alignment therewith in a normal skiing position, the bindingcomprising: a soleplate arranged for positioning in underlying contactwith the ski boot and for detachable connection thereto; at least onemounting element secured to the ski, said mounting element beingproximate said soleplate when the ski boot is in such skiing position;at least one connecting means carried by said soleplate for connectingsaid soleplate to said mounting element, said connecting meansincluding: a leash support on said soleplate; an elongated, flexibleleash supported at least partially on said leash support and connectedwith said mounting element, said leash being extendible and retractablefrom said leash support to permit said soleplate and mounting element tomove toward and away from one another and being in a retracted conditionwhen said mounting element is proximate said soleplate; and biasingmeans on said soleplate acting on said leash and including means forapplying a retraction force to said leash to resist separation of saidsoleplate from said position proximate said mounting element and controlmeans for varying the effectiveness with which said retraction force isapplied, said biasing means being responsive to a force, acting throughsaid leash and tending to separate said soleplate from said mountingelement, in excess of a predetermined magnitude to permit said leash toextend from its retracted condition and said soleplate to move out ofsuch skiing position and, thereafter, being responsive to reduction ofsuch separating force to a magnitude below the retraction force beingthen applied to said leash to initiate retraction of said leash towardits retracted condition and to continue such retraction so long as theseparating force is below the retraction force being then applied tosaid leash, until said leash returns to its retracted condition.
 2. Aski binding as defined in claim 1 wherein said biasing means functionsin two phases of operation, including a skiing phase in which thetension exerted on said leash is at a high level prior to initialseparation and, thereafter, decreases progressively at a rapid rate, anda release phase following separation over said initial range in whichthe tension exerted oN said leash by said biasing means is at arelatively lower level.
 3. A ski binding as in claim 1 wherein saidsoleplate and mounting element include cooperative guiding meansengageable to aid in aligning said soleplate with respect to said skiand in establishing its position longitudinally thereof when said leashis fully retracted to position the boot in skiing position.
 4. A skibinding as in claim 1 further including adjustment means on said leashsupport operatively associated with said biasing means for varying thetension exerted on said leash when said leash is retracted.
 5. A skibinding as in claim 4 wherein the tension force exerted on said leash bysaid biasing means is maximum when said leash is retracted.
 6. A skibinding as in claim 1 wherein said connecting means is operableautomatically upon extension of said leash and after the forces causingsuch extension have abated, to retract the same.
 7. A ski bindingcomprising: boot-engaging means adapted for connection to a ski boot; amounting element secured to the ski; connecting means carried by one ofsaid bootengaging means and mounting element and extending therebetweento serve as a force-applying link, said connecting means comprising: ahousing; a support member on said housing and mounted for rotationrelative thereto about an axis of rotation; a leash wound at leastpartially around said support member and arranged to be extended andretracted during rotation thereof, said leash at its point of separationfrom said support member being spaced from said axis of rotation by aradial distance defined as a leash moment arm; means for applying abiasing force to said support member at a radial distance from the axisof rotation thereof defined as a biasing moment arm, said biasing meansacting to apply a torque to said support member in a direction to windsaid leash onto said support member and thereby retract said leash; andratio means increasing the ratio of said leash moment arm to saidbiasing moment arm as said support member rotates in a direction toextend said leash, thereby decreasing the force required to producefurther extension thereof.
 8. A ski binding as defined in claim 7wherein said biasing means comprises a single spring connected with saidhousing and with said support member.
 9. A ski binding as defined inclaim 7 including adjustment means on said housing and operativelyassociated with said ratio means for adjustably establishing the initialratio of said leash moment arm to said biasing moment arm.
 10. A skibinding as defined in claim 9 wherein said leash moment arm remainssubstantially constant and said biasing moment arm varies duringrotation of said support member.
 11. A ski binding as defined in claim 9wherein said biasing moment arm remains substantially constant and saidleash moment arm varies during rotation of said support member.
 12. Aski binding as defined in claim 7 wherein said ratio is minimum when theleash is fully retracted and progressively increases during at least anintial portion of such leash extension and, thereafter, remainssubstantially constant during a further portion of such leash extension.13. A ski bonding coupling a ski boot on a ski and releasably holding itin alignment therewith in a normal skiing position, the bindingcomprising: a soleplate extending in underlying contact with the skiboot and connected thereto; heel and toe mounting elements secured tothe upper surface of the ski at locations spaced longitudinally thereof,said elements underlying and supporting said soleplate in the normalskiing position; heel and toe connecting means carried by said soleplateand extending between and serving as the force-applying links betweensaid soleplate and said mounting elements, each of said connecting meansincluding: a support fixed on said soleplate; a rotatable device mountedon said support for rotation relative thereto; A flexible leashsubstantially longer than the spacing between adjacent portions of saidsoleplate and said elements in said skiing position, said leash beingwound at least partially on said rotatable device and being extended andretracted during rotation thereof to permit said soleplate to move outof and back into said skiing position; and biasing means on said supportincluding means for urging said rotatable device to rotate in adirection to retract said leash and apply a tension force thereto andmeans for controlling the magnitude of said tension force as a functionof the extent of leash extension from a relatively high level when saidleash is retracted to a reduced level during extension thereof.
 14. Aski binding as in claim 13 wherein the tension force on said leash ismaximum when said leash is fully retracted and said soleplate is innormal skiing position, progressively reduces rapidly during initialextension thereof and remains substantially constant during furtherextension.
 15. A ski binding as in claim 13 wherein said heel connectingmeans is carried in generally upstanding orientation at the heel end ofsaid soleplate with its respective leash extending generally verticallydownwardly from its respective rotatable device to said heel mountingelement when said soleplate is in the normal skiing position.
 16. A skibinding as in claim 13 wherein said toe connecting means is carried in agenerally horizontal orientation on the underside of said soleplate withits respective leash extending generally horizontally from itsrespective rotatable device to said toe mounting element when saidsoleplate is in the normal skiing position.
 17. A ski binding as inclaim 13 wherein said soleplate and said toe mounting element are formedwith mating cam surfaces which engage when said leash of said toeconnecting means is retracted to center said soleplate relative to theski and thereby establish the normal skiing position.
 18. A ski bindingas in claim 17 wherein said forward mounting element includes a pivotallug that receives the end of said leash of said toe connecting means andis formed with one of said mating cam surfaces; and wherein said matingcam surfaces engage to prevent forward sliding movement of saidsoleplate longitudinally of the ski but permit lateral and rearwardmovement relative to said ski.
 19. A ski binding as defined in claim 13further including: heel guide means on said heel mounting element and onsaid soleplate to self-align said soleplate with the longitudinalcenterline of the ski when said soleplate is drawn into contact withsaid heel mounting element; and toe guide means on said toe mountingelement and on said soleplate to selfalign said soleplate with thelongitudinal centerline of the ski when said soleplate is drawn intocontact with said toe mounting element.
 20. A ski binding as defined inclaim 19 wherein one of said heel and toe guide means permitslongitudinal sliding motion of the adjacent surfaces of the soleplateand mounting element and the other prevents such longitudinal slidingmotion in at least one direction.
 21. A ski binding as defined in claim7, wherein said means for applying a biasing force includes, an axleconnected with said housing for rotation about a second axis of rotationparallel to the axis of rotation of said support member spacedtherefrom, torque means for applying torque to said second axle, andwherein said ratio means includes first and second, non-circular gearmembers connected to said support member and said axle in meshingengagement, the distance between the point of meshing engagement of saidgears and said axis of rotation of said support member defining saidbiasing moment arm, said gears being configured to move their point ofmeshing engagement progressively closer to the axis of rotation of saidsupport member as said support member rotates in a direction to uncoilsaid leash, thereby progressively reducing Said biasing moment arm. 22.A ski binding as defined in claim 12 wherein said ratio progressivelydecreases to another minimum value during a final portion of such leashextension following said further portion of such leash extension.
 23. Aski binding as defined in claim 14 wherein the tension force on saidleash progressively increases to another maximum value during a finalincreasing portion of leash extension following said further portion ofleash extension.
 24. A ski binding coupling a ski boot on a ski andreleasably holding it in alignment therewith in a normal skiingposition, the binding comprising: a soleplate arranged for positioningin underlying contact with the ski boot and for detachable connectionthereto, said soleplate being movable into and out of normal skiingposition; cooperating guides on said soleplate and mountable on said skiand located in underlying relationship with the soleplate when thelatter is in a normal skiing position, said guides engaging as saidsoleplate moves into such normal skiing position to aid in aligning saidsoleplate relative to the ski; and connecting means secured to andcarried by said soleplate, said connecting means including: aforce-applying link connected to the ski, said link being movablerelative to the said soleplate to permit said soleplate to move into andout of said normal skiing position; and biasing means including meansacting on said link to yieldably resist such movement thereof to permitsaid soleplate to move out of said normal skiing position and controlmeans for varying the magnitude of such resistance from a high levelwhen said soleplate is closely adjacent said ski to a reduced level whensaid soleplate has moved away from said ski.
 25. A ski binding as inclaim 24 wherein said link comprises an elongated, flexible leash.